1. Field of the Invention
The invention pertains to an ultrasonic test machine, especially for testing round stock, such as rods and pipes, with a rotor, which contains several probes and a transmission device with several channels for connecting the probes to a stationary electronic control and analysis unit.
2. Prior Art
In rotary test machines of this type, which have already been described in the book "J. and H. Krautkramer: Ultrasonic Material Testing [Werkstoffprufung mit Ultraschall], 4th ed., Springer-Verlag," the rotor, in which the probes are mounted, rotates at a high speed, e.g., up to 3000 rpm, about the tube or rod, which is being conveyed linearly through the axis of the rotor. Helical test tracks are formed on the surface of the tube. The probes located in the rotated rotor are controlled by a transmission device with several channels. In the previous test machine, slip rings are mounted next to each other in axial displacement from the actual rotor and are electrically connected to the probes. They are associated with stationary slip contacts, which in turn are connected to control and analysis electronics.
The applicant's previously known test machine of type ROT-FW has a transmission device for a total of ten probes. The associated slip ring system has an axial length approximately equal to the axial length of the rotor. The slip ring system used in this test machine is cost-intensive and must be replaced from time to time.
Ultrasonic rotary test systems of the type described above must have a very large range of dimensions of the testable tubes and rods, a high test sensitivity over the entire testable range of dimensions, adjustability of the probes or probe combinations for realizing different test functions and a high test speed. To meet these requirements, it is necessary to use different probes or probe combinations. For example, with only 10 probes in the applicant's previously known ROT-FW systems, it is not possible to perform all normally occurring US tests, not to mention the less frequently required tests. In state-of-the-art rotary test machines, the installed probes are changed when a different test function is to be performed. This means the expenditure of considerable labor and time and potential damage to the sensitive probes.
In principle, it is possible to mount a large number of probes in the rotor. However, to be able to connect these probes with the stationary control and analysis electronics, the transmission device must have a correspondingly large number of channels. Accordingly, to double the number of probes in the above-mentioned ROT-FW system, it would be necessary to practically double the number of channels of the transmission device. However, this would double the axial length of the slip ring system, which would have the following disadvantages: the system would become much longer, the rotor would be much heavier, and, above all, the costs for the transmission device would increase considerably.